Golf club shaft connection assembly

ABSTRACT

A golf club shaft connection assembly comprising first and second shaft sections, male and female adaptors, a hollow retainer, a spring, and a plurality of balls is disclosed herein. The male and female adaptors are each attached to the first and second shaft sections, respectively, preferably with a permanent adhesive. The male adaptor comprises a protrusion that fits within a keyed interior of the female adaptor, and moving the hollow retainer towards the male adaptor reversibly fixes the two adaptors together, while moving the hollow retainer towards the female adaptor allows the male adaptor to be removed from the female adaptor.

CROSS REFERENCES TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 15/059,167, filed on Mar. 2, 2016, and issued on Nov. 7, 2017,as U.S. Pat. No. 9,808,679, the disclosure of which is herebyincorporated by reference in its entirety herein.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a golf club shaft assembly that allowsfor quick, semi-permanent shaft adjustments. More specifically, thepresent invention relates to a connection system that permits a golferto adjust a shaft's characteristics, such as weight and length, usingshaft components having different lengths.

Description of the Related Art

Customization of golf clubs to help golfers attain better shots hasbecome a popular and more prevalent practice in recent years. Golf clubmanufacturers and designers have devised various features to allow clubfitters and golf club players to adjust certain characteristics of theirclubs. Such characteristics include loft, lie, face angle, center ofgravity (CG) location, and club length.

Current technology provides two commonly used methods to adjust overallclub length. One such method involves the destruction and removal of thegrip on a shaft. Upon removal of the grip by peeling or tearing, the endportion of the shaft is trimmed to decrease the club length or anextension piece is affixed to the end of the shaft to increase itslength. Aftermarket extensions are available specifically for thispurpose; alternatively, extensions can be made from portions of othergolf club shafts that are cut to the desired length and then insertedinto the end of the first club's shaft. The extension piece must matchthe diameter of the existing shaft, so it is necessary at times to buildup the diameter of the extension or existing shaft by adding layers oftape. This method requires that the user making the adjustments haveaccess to potentially expensive new components and tools as well ashaving a high level of skill. It also causes damage to the originalshaft and grip.

The second method of adjusting club length involves replacing the entireshaft and grip using a semi-permanent head-shaft connection device thatsome manufacturers offer with their clubs, particularly with drivers.The existing shaft may be removed from the driver head and replaced witha different shaft that has either a shorter or longer length. Thismethod is not possible on all clubs, however, as the head must havehardware that allows for removal of the shaft and replacement with a newshaft without damaging the head.

A golfer who does not possess club altering skills or the necessarydisposable income to purchase new components likely will be daunted bythese two methods of adjusting club length. The first method requiresthe golfer to make use of several tools to remove the grip and cut theshaft if he or she desires a shorter length, and also to have materialssuch as tape and a replacement grip on hand to replace the grip and mendany damage caused to the shaft and grip. The skill set required tochange the shaft length using this method is usually beyond theabilities of the average golfer, so the golfer would need to seek theservices of a golf club fitter or technician to have their club lengthchanged. The second method requires the golfer to buy an entirely newshaft at a different length, which can be very expensive, and also mayrequire the golfer to retain a golf club fitter or technician to replacethe shaft.

Ultimately, the two methods described above require an inventory ofspare components and above average technical skill, particularly withregard to the first method. It is therefore desirable to facilitate thechange of a club's length using a faster, easier, and less expensiveconnection system and method than is currently available.

BRIEF SUMMARY OF THE INVENTION

One aspect of the present invention is a shaft connection assembly thatpermits a golfer to quickly and securely adjust the length of his or hergolf club shaft. The assembly can include upper shaft portions ofvarying lengths and a single lower shaft portion or a golf club headwith a hosel portion. The connection assembly includes male and femaleadaptors, a spring, a plurality of metal balls, and a retainer.

Another aspect of the present invention is a golf club shaft connectionassembly comprising a golf club head, a first shaft section, a secondshaft section, a male adaptor comprising a first body portion, a firstprotrusion, and a first ledge portion between the first body portion andthe first protrusion, a female adaptor comprising a second body portion,a second protrusion, and a second ledge portion between the second bodyportion and the second protrusion, a hollow retainer comprising a firstupper end, a first lower end, and an internal flange disposed proximatethe first upper end, a spring comprising a second upper end and a secondlower end, and a plurality of balls, wherein each of the first bodyportion and the second body portion is affixed to one of the first shaftsection and the second shaft section, wherein the golf club head isaffixed to one of the first shaft section and the second shaft section,wherein the first protrusion comprises a stem portion, a keyed portion,and a first groove between the stem portion and the keyed portion,wherein the second protrusion comprises a base portion and a hollowextension, wherein the hollow extension comprises an external surface, asecond upper end, a second lower end proximate the base portion, a keyedinterior, and a plurality of circular through-bores disposed proximatethe second upper end, wherein the hollow retainer is disposed around thehollow extension such that the internal flange is located proximate thesecond upper end, wherein the internal flange comprises an upper surfaceand a lower surface, wherein the spring is coiled around the hollowextension such that the second lower end abuts the base portion and thesecond upper end abuts the lower surface of the internal flange, whereineach of the plurality of balls is partially disposed within one of theplurality of circular through-bores above the upper surface of theinternal flange, wherein the keyed portion is sized to fit within thekeyed interior, and wherein moving the retainer towards the first ledgeportion removably fixes the male adaptor to the female adaptor.

In some embodiments of the present invention, the plurality of circularthrough-bores may encircle the upper end of the hollow extension. Inother embodiments, the keyed portion may comprise a plurality of secondgrooves, and each of the plurality of second grooves may be linear andmay comprise a concave cross-section. In a further embodiment, the keyedinterior may comprise a plurality of ridges, and each of the pluralityof ridges may be sized to fit within one of the plurality of secondgrooves, which may comprise four linear grooves. In some embodiments,the first groove may encircle the first protrusion and may comprise aconcave cross-section. In a further embodiment, each of the plurality ofballs may engage the first groove when the first upper end abuts thefirst ledge portion.

In one embodiment, the golf club shaft connection assembly may furthercomprise a retainer clip, which may be affixed to the upper end of thehollow extension above the through-bores and the upper surface of theinternal flange, and each of the plurality of balls may be disposedbetween the retainer clip and the upper surface of the internal flange.In other embodiments, each of the plurality of balls may comprise afirst diameter, each of the plurality of through-bores may comprise asecond diameter, and the first diameter may be greater than the seconddiameter. In yet another embodiment, the hollow retainer may have afirst length and the hollow extension may have a second length that maybe greater than the first length.

In some embodiments, the upper surface of the internal flange may beangled and the lower surface of the internal flange may be planar. Inothers, each of the first and second body portions may be hollow. Insome embodiments, the hollow retainer may be a cylindrical tube. Instill other embodiments, each of the first and second body portions maycomprise external ribs. In a further embodiment, each of the first shaftsection and second shaft section may be hollow, and each of the firstbody portion and the second body portion may be affixed within one ofthe first shaft section and the second shaft section. In anotherembodiment, each of the first and second body portions may bepermanently affixed within one of the first shaft section and the secondshaft section with an adhesive material.

In any of the embodiments, each of the first and second shaft sectionsmay be composed of a steel material. In any of the embodiments, each ofthe male adaptor, female adaptor, spring, plurality of balls, and hollowretainer may be composed of a metal material, which may be selected fromthe group consisting of titanium alloy, aluminum alloy, and steel. Inother embodiments, the golf club head may be a putter-type head.

Having briefly described the present invention, the above and furtherobjects, features and advantages thereof will be recognized by thoseskilled in the pertinent art from the following detailed description ofthe invention when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is an elevational view of a golf club head incorporating theconnection assembly of the present invention

FIG. 2 is a side elevational view of the connection assembly circled inFIG. 1 in an open configuration, without the shaft sections.

FIG. 3 is a side perspective view of the connection assembly shown inFIG. 2.

FIG. 4 is a side perspective view of the male adaptor piece of theconnection assembly shown in FIG. 2.

FIG. 5 is a side perspective view of the connection assembly shown inFIG. 2 with the male adaptor piece removed.

FIG. 6 is a side elevational view of connection assembly shown in FIG. 5with the hollow retainer removed.

FIG. 7 is a side perspective view of the female adaptor piece shown inFIG. 6 engaged with the retainer clip and a single metal ball.

FIG. 8 is a cross-sectional view of the connection assembly shown inFIG. 2 along lines 8-8 in a closed configuration.

FIG. 9 is a cross-sectional view of the connection assembly shown inFIG. 8 in an open configuration.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to a golf club shaft connectionassembly that permits golfers to adjust the overall length of their clubshafts. Shaft length adjustability is an advantageous feature for golfclubs, and particularly drivers, because extending the length of a clubcan increase club head speed, which results in longer driving distances.Conversely, shortening the length of a club's shaft can provide a golferwith more control and accuracy in driving the golf ball. Golf courseconditions often require accurate driving due to hazards, including butnot limited to water, rough, and out of bounds markers, and drivingaccuracy can be more preferred than driving distance in competitivesituations.

The present invention is also valuable because a golfer's swing maychange over time, thus requiring alterations to his or her clubs. Agolfer may improve his or her game through lessons and may gain greaterflexibility and strength through practice and exercise. Therefore, it isreasonable for a golfer to wish to change his or her club's length tohelp improve his or her accuracy, distance, and feel as needed ordesired.

The present invention provides golfers with a system that allows them toquickly and inexpensively modify the length of their golf clubs so theyperform in a desired manner. This invention will enable golfers tochange their club length wherever they wish, including, but not limitedto, at the practice range, the golf course, and their home. The presentinvention also is designed to avoid altering a club's swing weight orits “feel.” No tools are required to make an adjustment, and thetechnical ability required to modify the golf club length according tothis invention is minimal and its approach is intuitive and easy for agolfer to understand.

A preferred embodiment of the shaft connection assembly 100 of thepresent invention is shown in FIGS. 1-9. According to this embodiment ofthe invention, and as shown in FIG. 1, two hollow sections of the shaft10, the lower shaft section 12, which may be permanently or removablyconnected to a golf club head 16, and the upper shaft section 14, whichincludes a grip 18, are joined together along a demarcation line 15, theline at which the two shaft sections 12, 14 meet. The shaft sections 12,14 are connected to one another with the connection assembly 100 shownin FIGS. 2-9, which comprises a male adaptor 20, a female adaptor 40, ahollow retainer 60, a retainer clip 80, a spring 90, and at least twoballs 92, 94 made of metal or another resilient material.

As shown in FIGS. 4, 8, and 9, the male adaptor 20 includes a hollowbody portion 22 with an outer surface 23 having a plurality of ribs 24extending along the length of the body portion 22, a hollow interior 25,a ledge portion 26 disposed at a lower end of the body portion 22, and acontoured protrusion 30 extending perpendicularly away from the ledgeportion 26. The hollow interior 25 reduces the overall mass of the maleadaptor 20, the body portion 22 of which is inserted into a hollowinterior of either the lower or upper shaft sections 12, 14 and thenbonded therein. The ribs 24 allow the body portion 22 to fit moresecurely inside one of the shaft sections 12, 14 and provide additionalbonding surface for whichever adhesive is applied to the outer surface23 to bond the male adaptor 20 to the shaft section 12, 14.

The contoured protrusion 30 preferably is a solid piece that includes astem portion 32, a keyed bulb portion 34 including a plurality ofconcave linear grooves 36 extending along most of the length of the bulbportion 34, and a concave groove 33 encircling the contoured protrusion30 and separating the stem portion 32 from the bulb portion 34. In thepreferred embodiment, the bulb portion 34 is approximately rectangularand has four concave linear grooves 36, one extending along eachlongitudinal side of the bulb portion 34. Each of the concave lineargrooves 36 has a cross-sectional curvature that matches the curvature ofthe at least two balls 92, 94.

As shown in FIGS. 3 and 5-9, the female adaptor 40 also includes a bodyportion 42 with an outer surface 43 comprising a plurality of ribs 44extending along the length of the body portion 42, a hollow interior 45,a ledge portion 46 disposed at a lower end of the hollow body portion42, and a contoured protrusion 50 extending perpendicularly away fromthe ledge portion 46. The hollow interior 45 reduces the overall mass ofthe female adaptor 40, the body portion 42 of which is inserted into ahollow interior of either the lower or upper shaft sections 12, 14 andthen bonded therein. The ribs 44 allow the body portion 42 to fit moresecurely inside one of the shaft sections 12, 14 and provide additionalbonding surface for whichever adhesive is applied to the outer surface43 to bond the female adaptor 40 to the shaft section 12, 14.

The contoured protrusion 50 includes a solid base portion 52 and acylindrical, hollow extension 54 with a ridged, keyed interior 56 sizedto receive the contoured protrusion 30 of the male adaptor 20. The upperend 55 of the hollow extension 54 comprises a plurality of through-bores57 sized to receive the at least two balls 92, 94. The through-bores 57are circular and have a diameter that is slightly smaller than that ofthe balls 92, 94, such that the balls 92, 94 cannot completely fitthrough the through-bores 57, and instead can only rest partially withinthe through-bores 57 at the external surface 58 of the hollow extension54. As shown in FIG. 6, the spring 90 is coiled around the circumferenceof the hollow extension 54 such that a first end 91 of the spring 90abuts the base portion 52, while the retainer clip 80 encircles theupper end 55 of the hollow extension 54 above the through-bores 57.

As shown in FIGS. 2, 3, and 5, the retainer 60 is a cylindrical tubethat receives, and almost completely obscures, the hollow extension 54portion of the female adaptor 40. The retainer 60 includes an upper end62 and a lower end 64, each of which abuts a ledge portion 26, 46 on oneof the male adaptor 20 and female adaptor 40, respectively, when theconnection assembly 100 is fully assembled and in a closed position. Theretainer 60 also includes an internal flange 65 extending from aninterior surface 61 proximate the upper end 62. The internal flange 65has a planar lower surface 66 and an angled upper surface 67 that taperstowards the interior surface 61 of the retainer 60. The retainer 60 hasa length L₁ that is slightly less than that of the length L₂ of thehollow extension 54 so that there is room for the retainer 60 to movealong the longitudinal axis 105 of the connection assembly 100.

As shown in FIGS. 8 and 9, when the retainer 60 is engaged with thehollow extension 54, the internal flange 65 is located slightly belowthe through-bores 57 encircling the upper end 55 of the hollowextension, and the spring 90 is trapped between the planar lower surface66 of the internal flange 65 and the base portion 52 of the hollowextension 54. The retainer clip 80 is disposed above the internal flange65 and, when attached to the upper end 55 of the hollow extension 54,prevents the retainer 60 from falling off of the hollow extension 54.The dimensions of the retainer clip 80 and the retainer 60 serve toprevent the balls 92, 94 from disengaging from the connection assembly100, while still giving them room to move.

FIGS. 8 and 9 illustrate how the parts of the connection assembly 100fit together and operate. FIG. 8 shows the connection assembly in a“closed” configuration, in which the contoured protrusion 30 of the maleadaptor 20 is trapped within the hollow extension 54 of the femaleadaptor 40 so that the shaft sections 12, 14 are fixed together. FIG. 9shows the connection assembly in an “open” configuration, in which themale adaptor 20 can be removed from the female adaptor 40 and thereforethe shaft sections 12, 14 can be separated from one another.

The upward force exerted by the spring 90 causes the “closed”configuration to be the default state of the connection assembly 100. Inthis state, when the concave linear grooves 36 of the bulb portion 34mate with the ridges in the keyed interior 56 of the hollow extension 54so that the contoured protrusion 30 is fully engaged with the hollowextension 54, the spring 90 pushes the internal flange 65, and thus theretainer 60, away from the base portion 52 of the contoured protrusion50 until the upper end 62 of the retainer 60 abuts the ledge portion 26of the male adaptor 20. In doing so, the angled upper surface 67 of theinternal flange 65 forces each of the balls 92, 94 further into theirrespective through-bores 57 such that they make contact with, and applypressure to, the concave groove 33 on the bulb portion 34 of thecontoured protrusion 30. The pressure from the balls 92, 94 serves tolock the contoured protrusion 30 within the keyed interior 56 of thehollow extension 54.

The connection assembly 100 is placed in the “open” configuration when agolfer pulls the retainer 60 downwards towards the body portion 42 ofthe female adaptor 40 until the lower end 64 abuts the ledge portion 46of the female adaptor 40. This motion compresses the spring 90 betweenthe internal flange 65 and the base portion 52, such that, if theretainer 60 is released, it will automatically revert into its lockedconfiguration. Moving the retainer 60 towards the body portion 42 of thefemale adaptor releases the pressure placed by the internal flange 65 ofthe retainer 60 on the balls 92, 94, which disengage from thethrough-bores 57 enough to release the pressure on the concave groove 33of bulb portion 34 of the contoured protrusion 30. This effectively“unlocks” the contoured protrusion 30, and thus the male adaptor 20,from the hollow extension 54 of the female adaptor 40.

The parts of the connection assembly 100 of the present invention may becomposed of any number of materials, including metals, plastics,rubbers, and composites. The shaft sections 12, 14, adaptors 20, 40,retainer 60, retainer clip 80, and balls 92, 94 may be composed oftitanium, graphite or carbon composite, plastic, magnesium, aluminum,steel, or alloys of such materials, specifically stainless steel 17-7 ortitanium 6-4. The shaft sections 12, 14 preferably are composed ofgraphite or steel. The grip 18 preferably is composed of a rubbermaterial. The adaptors 20, 40, retainer 60, retainer clip 80, and balls92, 94 preferably are composed of a metal material, and most preferablya stainless steel material. The golf club head 16 preferably is adriver-type head, but may in alternative embodiments be a putter-typehead, a fairway wood-type head, an iron-type head, a hybrid-type head,or a wedge-type head.

From the foregoing it is believed that those skilled in the pertinentart will recognize the meritorious advancement of this invention andwill readily understand that while the present invention has beendescribed in association with a preferred embodiment thereof, and otherembodiments illustrated in the accompanying drawings, numerous changes,modifications and substitutions of equivalents may be made thereinwithout departing from the spirit and scope of this invention which isintended to be unlimited by the foregoing except as may appear in thefollowing appended claims. Therefore, the embodiments of the inventionin which an exclusive property or privilege is claimed are defined inthe following appended claims.

I claim as my invention:
 1. A shaft connection assembly comprising: afirst shaft section; a second shaft section; a male adaptor comprising afirst body portion, a first protrusion, and a first ledge portionbetween the first body portion and the first protrusion; a femaleadaptor comprising a second body portion, a second protrusion, and asecond ledge portion between the second body portion and the secondprotrusion; a hollow retainer comprising a first upper end, a firstlower end, and an internal flange disposed proximate the first upperend; a spring comprising a second upper end and a second lower end; anda plurality of balls, wherein each of the first body portion and thesecond body portion is affixed to one of the first shaft section and thesecond shaft section, wherein the first protrusion comprises a stemportion, a keyed portion, and a first groove between the stem portionand the keyed portion, wherein the second protrusion comprises a baseportion and a hollow extension, wherein the hollow extension comprisesan external surface, a second upper end, a second lower end proximatethe base portion, a keyed interior, and a plurality of circularthrough-bores disposed proximate the second upper end, wherein thehollow retainer is disposed around the hollow extension such that theinternal flange is located proximate the second upper end, wherein theinternal flange comprises an upper surface and a lower surface, whereinthe spring is coiled around the hollow extension such that the secondlower end abuts the base portion and the second upper end abuts thelower surface of the internal flange, wherein each of the plurality ofballs is partially disposed within one of the plurality of circularthrough-bores above the upper surface of the internal flange, whereinthe keyed portion is sized to fit within the keyed interior, and whereinmoving the retainer towards the first ledge portion removably fixes themale adaptor to the female adaptor.
 2. The shaft connection assembly ofclaim 1, wherein the plurality of circular through-bores encircles theupper end of the hollow extension.
 3. The shaft connection assembly ofclaim 1, wherein the keyed portion comprises a plurality of secondgrooves, and wherein each of the plurality of second grooves is linearand comprises a concave cross-section.
 4. The shaft connection assemblyof claim 3, wherein the keyed interior comprises a plurality of ridges,and wherein each of the plurality of ridges is sized to fit within oneof the plurality of second grooves.
 5. The shaft connection assembly ofclaim 3, wherein the plurality of second grooves comprises four lineargrooves.
 6. The shaft connection assembly of claim 1, wherein the firstgroove encircles the first protrusion and comprises a concavecross-section.
 7. The shaft connection assembly of claim 6, wherein eachof the plurality of balls engages the first groove when the first upperend abuts the first ledge portion.
 8. The shaft connection assembly ofclaim 1, further comprising a retainer clip, wherein the retainer clipis affixed to the upper end of the hollow extension above thethrough-bores and the upper surface of the internal flange, and whereineach of the plurality of balls is disposed between the retainer clip andthe upper surface of the internal flange.
 9. The shaft connectionassembly of claim 1, wherein each of the plurality of balls comprises afirst diameter, wherein each of the plurality of through-bores comprisesa second diameter, and wherein the first diameter is greater than thesecond diameter.
 10. The shaft connection assembly of claim 1, whereinthe hollow retainer has a first length, wherein the hollow extension hasa second length, and wherein the second length is greater than the firstlength.
 11. The shaft connection assembly of claim 1, wherein the uppersurface of the internal flange is angled, and wherein the lower surfaceof the internal flange is planar.
 12. The shaft connection assembly ofclaim 1, wherein each of the first and second body portions is hollow.13. The shaft connection assembly of claim 1, wherein the hollowretainer is a cylindrical tube.
 14. The shaft connection assembly ofclaim 1, wherein each of the first and second body portions comprisesexternal ribs.
 15. The shaft connection assembly of claim 14, whereineach of the first shaft section and second shaft section is hollow, andwherein each of the first body portion and the second body portion isaffixed within one of the first shaft section and the second shaftsection.
 16. The shaft connection assembly of claim 15, wherein each ofthe first and second body portions is permanently affixed within one ofthe first shaft section and the second shaft section with an adhesivematerial.
 17. The shaft connection assembly of claim 1, wherein each ofthe first and second shaft sections is composed of a steel material. 18.The shaft connection assembly of claim 1, wherein each of the maleadaptor, female adaptor, spring, plurality of balls, and hollow retaineris composed of a metal material.
 19. The shaft connection assembly ofclaim 18, wherein the metal material is selected from the groupconsisting of titanium alloy, aluminum alloy, and steel.
 20. The shaftconnection assembly of claim 19, wherein the metal material is steel.